A generic description of Stenanthemum Reissek is given, together with a key and distribution maps for the 23 species occurring in Western Australia. Stenanthemum leucophractum (Schledl.) Reissek is nominated as the type species of the genus. Three new species from south-western Australia, Stenanthemum liberum Rye, S. patens Rye and S. sublineare Rye, are described and illustrated, and new seed measurements are given for S. cristatum Rye. All of the new species have conservation priority.